61. During which stage of meiosis do sister chromatids separate and move to opposite poles of the cell?
Answer: C
Sister chromatids separate and move to opposite poles during Anaphase II.
During Anaphase II of meiosis, sister chromatids are pulled apart and migrate to opposite poles of the cell, ensuring that each daughter cell will receive an identical set of chromosomes.
A) Prophase II
Prophase II is the stage where the nuclear envelope breaks down again and the spindle apparatus forms, but sister chromatids do not separate during this phase. Therefore, this option is incorrect as it does not involve the separation of sister chromatids.
B) Prophase I
Prophase I is characterized by the pairing of homologous chromosomes and the exchange of genetic material through crossing over. This phase does not involve the separation of sister chromatids, making this option incorrect.
C) Anaphase II
Anaphase II is the correct answer as it is during this phase that the sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell. This is a crucial step in meiosis that ensures each gamete receives just one copy of each chromosome.
D) Anaphase I
Anaphase I involves the separation of homologous chromosomes, not sister chromatids. In this phase, each homologous chromosome is pulled to opposite poles, which is a different process than the separation of sister chromatids. Thus, this option is incorrect.
Conclusion
Anaphase II is definitively the correct answer because it specifically describes the stage at which sister chromatids separate, a critical event in meiosis. The other options either describe stages that involve different processes or do not pertain to the separation of sister chromatids at all.